I just had tested Alexa mini Open Gate 3.4K RAW and Blackmagic Ursa mini 4.6K RAW in extreme contrast scene.
No any lighting added. I had the very strong sun light in the back, and only 1 fluorescent lamp in the scene.
Lens was Tokina 16-28 and 50-135 T3.0 PL.

I had loaded original footage into DaVinci Resolve Studio 12.5.4 for creating 1920×1080 25p ProRes 422HQ as proxies. I edited from proxies then uploaded to web.
The original Alexa 3.4K RAW and Blackmagic mini 4.6K RAW will be uploaded later.